Rapid cognitive decline: not always Creutzfeldt-Jakob disease.

A patient with rapidly progressive cognitive decline over an approximately four month period was suspected to have sporadic Creutzfeldt-Jakob disease. Features thought to support this diagnosis included psychiatric symptoms (anxiety and depression), visual hallucinations and a visual field defect. However, the finding of papilloedema broadened the differential diagnosis. Although standard brain imaging and electroencephalography had shown only non-specific abnormalities, subsequent cerebral angiography disclosed an intracranial dural arteriovenous fistula. Following embolisation, the patient made a good functional recovery. Intracranial dural arteriovenous fistula merits consideration in any patient with subacute cognitive decline, and should be included in the differential diagnosis of sporadic Creutzfeldt-Jakob disease.